Method for the precipitation and preparation of compressed yeast



Ill

Ill

Fetented Mar. 2, IQZQ.

names are tnant errant ensues.

FRIEDRICH HAYIDUGK, OI WILMERSDORI, GERMANY, ASSIGNOR TO THE JIIJEISCH- MANN CUIIPANY, 013 NEW YORK, N. in, A GORJPORAIIUN OI OHIQ.

METHOD IQIt THE PRECIPITATION AND PREPARATIUN OI: COMPRESSED YEAST.

We Drawing. I

Appltcatlon filed oototer 30, mm). serial 130. $0,846

(GRANTED UNDER THE PRQWISIOIIS OF THE A61 015 HAIWII 3,1921, 41 STAT. I, I818.)

To all whom e't may concern:

Be it known that I, Fninimron HAYDUCK, a citizen of Germany, residing at Wilmersdorf, Germany, have invents certain new and useful Improvements in Methods for the Precipitation and Preparation of Compressed Yeast (for which up lication for atent was filed in German was 26, 19 15, atent No. 300,664), of which the followmp is a specification. Th1s invention relates to a method of settlin and separating yeast from the liquid in W%1l0h it has been propagated and has for its object an improved procedure for rapidly, efficiently and economically achieving this result.

Another object is to provide a method preparing yeast in a marketable condition which is convenient and economical.

At the time that the processes of the manufacture of aerated yeast had not yet reached their present volume, it was customary to separate the yeast from the spent wort by allowing the yeast to settle in a suitable preci itation vat, and thereafter pressin it to re ease it from the adhering liquid. t was observed, however, that the lower the degree of acidity of the liquid in which the yeast was grown the more perfect was the flocculation and settling'or precipitating of the yeast. However, since the biological purity of the yeast is impaired by the long stay during settling or precipltation in till liquids having low acidity, centrifugals (separators) were employed which made it possible to free even pulverulent yeast quickly from the fermented or s ent wort.

I have now ascertained that it is possible fully and quickly to recipitate even a comletely pulverulent dusty) yeast from the ermented or spent wort b adding to the same, after the end of t e propagating period, alkalies (e. g. soda lye, soda, lime water, etc.) until a weakly alkaline reaction is reduced. As a result of this the cast will conglomerate and will then sett e or recipitate from the wort, whereby it will he possible'to draw oil the clear superna tant liquid from the settled yeast.

As an example of the manner in which this method may be carried out the followin is given:

he yeast may be grown in a wort of any suitable composition (e. g. grain worts, sugansalt worts, molasses worts, worts preiared from industrial waste liquors, etc.) in accordance with the usual methods of manufacture. As soon as the period of propagation 1s completed the yeast is settled either in the fermentation vat itself or in asuitable settling vat, by the addition of alkali. The quantity of alkali which needbe employed is very small. F or example, 1n worts of neutral reaction the addition of from 5 to grams of caustic soda per hectoliter of yeast containin liquid is suiiicient. From a solution whic has been so treated east will settle in a short time, for examp e, within ten minutes. The supernatant liquid is then removed and the yeast in the remaining liquid may be acidified by the addition of a small amount of mineral acid prior to pressing in order to avoid infections.

Having described my invention, what I claim as new and desire to secure by Letters Patent is 1. A method of settling yeast from a liquid in which it is sus ended which comprises renderin the liquid slightly alkaline.

2. A metho of settling yeast from a liquid in which it is suspended which comprises rendering the liquid slightly alkaline by the addition of a substance having an a kaline reaction.

.3. A method ofsettling yeast from a liquid in which it is suspended which comprises rendering the liquid slightly alkaline by the addition of an alkali.

4. A method of settling yeast from a liquid in which it is suspended which comvrises inducing recipitation and settling y the addition 0 caustic soda.

5. Ihe method of settling yeast from residual liquid nutrient solutions used in the manufacture of yeast by the aeration rocess and after termination of the period 0 propagation, which comprises adding an alkali to the yeast containing solution until a weakly alkaline reaction is produced. I

6. The method of separating yeast from the excess of s ent wort in which it has been propagated w llCh comprises rendering the wort slightly alkaline by the addition of an alkali, allowing the yeast to settle, and withdrawing the supernatant liquid.

7 .-In a method of preparing compressed yeast, the steps which comprise separating the yeast from the spent wort in which it has been propagated, by the addition of an 5 alkali until a weakly alkaline reaction is produced, allowing the yeast to settle, withdrawing the supernatant liquid, rendering the residual liquid in which the yeast is sus-- pended slightly acid by the addition of a mineral acid, and subjecting the suspension 10 t0 the action of a filter press.

In testimony whereof, I have afiixed my signature. v

FRIEDRICH HAYDUCK. 

